The usual panoply of watersports are available, including plenty of dive shops, but most diving is done either in the nearby Ang Thong National Marine Park or Ko Tao as the visibility around Samui's sandy beaches tends to be poor. You can book diving day trips at dive shops, most of which are based in Chaweng. The dive boats tend to leave from the pier at Bophut and Bang Ruk.
Diving
The south of Thailand has some of the most beautiful beaches and islands in the world, which are surrounded by crystal clear water and stunning coral. For this reasons the number of divers coming to Thailand has steadily increased over the past decade. Even though the best time year of the year to dive in the Ko Samui is between June and August, it is still perfectly possible to dive virtually all year round. As Thailand is considered one of the safest destinations for diving and snorkelling in the world, it is perfect for first-timers.
The sea visibility in some places around Ko Samui is good (distances of up to 10-30 m). One can enjoy splendid sights of underwater mountains, coral gardens, undersea rock formations, hard and soft coral, and whale sharks when in season.
'Samran Pinnacles:' Since the currents in this area are often quite strong, this site is recommended only for experienced divers. Due to the currents, the site is a haven for bringing in larger pelagics such as barracuda and jacks. There are three submerged pinnacles near Sail Rock.
'Ko Kra & Koh Losin:' These two small islands located to the southeast of Samui, which because of its remoteness, don’t get too many divers. Blacktip sharks, manta rays, and hard-to-find loggerhead turtles can be seen.
'Ko Tan:' (also Known as Koh Tan, Koh Taen, Koh Kataen, Coral Island and affectionately as No Dog Island. This small island is located on the south-western tip of Samui. This is a perfect place for experiencing the wonders of snokeling. Local experts tell travelers is gthe perfect location for people that don't wish to travel two plus hours for snorkeling. located only 15 minutes from Samui there are over 14 sites for travelers to visit with an abundance of underwater life including soft and hard corals. There are many longtail boats available to tourists from Thong krut at more than reasonable prices. If you want to go to Ko Tan you can Book through any good travel agent or research the Internet, 0r go to Thong krut directly. At Ko Tan, there are Five restaurants Ao-Ok bay has Three restaurants one at either end of the beach both with accommodation and run by local people with excellent tasting Thai cuisine. the third for this beach is located in the middle and owned by a French gentleman. On the opposite side of the island is a beautiful bay called Ao-Tok where there is 2 restaurants and 2 lots of accommodation serving excellent tasting food. The accommodation is of high standard for the 500THB asking price Ko Tan is surrounded by coral and rock reefs, there are some 10 beaches that can be found around the island. The populations is currently 28 permanent residents and the People are friendly.